The dispersion equations are derived analytically for normal elastic waves in a longitudinally anisotropic cylindrical waveguide with circular cross-section and a sector-shaped channel of arbitrary angular measure. The boundary surfaces of the channel are covered with flexible, inextensible membranes. The cylindrical portion of the lateral surface is rigidly fixed. A numerical analysis of the dispersion equations reveals spectral branches of traveling normal waves with different types of symmetry of cross-sectional displacements and different circumferential wave numbers. Some features of the spectrum due to variation in the angular measure are established Keywords: longitudinally anisotropic cylindrical waveguide, sector-shaped channel, traveling normal waves, dispersion spectrumThe varying properties of the dispersion spectra of harmonic normal strain waves in elastic cylindrical waveguides and the possibilities to control the structure of dispersion spectra by varying the geometry of the cross-section and the mechanical properties of the waveguide and using the effects of coupling of physicomechanical fields or filling hollow cylindrical waveguides with a fluid are issues partially generalized in [1-4] and remaining important for wave mechanics [5][6][7][8][9][10][11].The present paper discusses results describing the changes in the structure of the dispersion spectra of traveling normal waves in longitudinally anisotropic cylindrical waveguides of sector-shaped cross-section with a variable angular measure (Fig. 1). The waveguide occupies the following domain described in dimensionless cylindrical coordinates: V = {r ∈ [0, R * ], θ ∈ [α, 2π -α], z ∈ (-∞, ∞)}. The cross-sectional boundary G = G 0 ∪ G + ∪ G -of the waveguide consists of the following sections G 0 = {r = R * , α ≤ θ ≤ 2π -α}, G + = {0 ≤ r ≤ R * , θ = α}, and G -= { 0 ≤ r ≤ R * , θ = -α}. The section G 0 is fixed, and the sector-shaped channel, G + and G -, is covered with perfectly elastic, inextensible membranes. These boundary conditions are expressed aswhere { }( , , ) u r z α α θ = are the dimensionless components of the vector intensity function r r u u r e i t kz = − − 0 ( , ) (~) θ ω for a harmonic normal wave, and { }( , , , , ) σ αβ θ θθ θ αβ = rr r rz z are dimensionless complex elastic-stress functions for normal waves. The dispersion equation for the normal waves in question is derived analytically. By integrating the stationary dynamic equations of an anisotropic hexagonal-system medium with OZ as a collinear symmetry axis, we obtain the dimensionless normalized components of the complex amplitude vector r u 0 of wave displacements: u r